This famous story about the monkey and the crocodile has traveled all around the world; you can see some different versions at Dan Ashliman's website: The Monkey's Heart. In this lifetime, the Buddha was born as a great monkey, relying on his quick wits to escape his enemies, the crocodiles. The word "jataka" means "birth," so the Jataka Tales are actually stories of the Buddha's previous births, and in the traditional version, each Jataka has a little poem that conveys the moral of the story, as you will see here. By choosing to return again and again with another birth, the Buddha is a Bodhisatta (Bodhisattva); you can find out more about the Bodhisattva tradition at Wikipedia.
Story source: Eastern Stories and Legends by Marie L. Shedlock.
THE CROCODILE AND THE MONKEY'S HEART
Once upon a time, while Brahmadatta was king of Benares, the Bodhisatta came to life at the foot of Himalaya as a Monkey. He grew strong and sturdy, big of frame, well-to-do, and lived by a curve of the river Ganges in a forest haunt.
Now at that time there was a Crocodile dwelling in the Ganges. The Crocodile's mate saw the great frame of the monkey, and she conceived a longing for his heart to eat. So she said to her lord, "Sir, I desire to eat the heart of that great king of the monkeys!"
"Good wife," said the Crocodile, "I live in the water and he lives on dry land: how can we catch him?"
"By hook or by crook," she replied, "caught he must be. If I don't get him, I shall die."
"All right," answered the Crocodile, consoling her, "don't trouble yourself. I have a plan; I will give you his heart to eat."
So when the Bodhisatta was sitting on the bank of the Ganges, after taking a drink of water, the Crocodile drew near and said: "Sir Monkey, why do you live on bad fruits in this old familiar place? On the other side of the Ganges there is no end to the mango trees, and labuja trees, with fruit sweet as honey! Is it not better to cross over and have all kinds of wild fruit to eat?"
"Lord Crocodile," the Monkey made answer, "deep and wide is the Ganges: how shall I get across?"
"If you will go, I will mount you on my back and carry you over."
The Monkey trusted him, and agreed. "Come here, then," said the other; "up on my back with you!" and up the Monkey climbed. But when the Crocodile had swum a little way, he plunged the Monkey under the water.
"Good friend, you are letting me sink!" cried the Monkey. "What is that for?"
Said the Crocodile, "You think I am carrying you out of pure good nature? Not a bit of it! My wife has a longing for your heart, and I want to give it to her to eat!"
"Friend," said the Monkey, "it is nice of you to tell me. Why, if our heart were inside us when we go jumping among the tree-tops, it would be all knocked to pieces!"
"Well, where do you keep it?" asked the other.
The Bodhisatta pointed out a fig-tree, with clusters of ripe fruit, standing not far off. "See," said he, "there are our hearts hanging on yon fig-tree."
"If you will show me your heart," said the Crocodile, "then I won't kill you."
"Take me to the tree, then, and I will point it out to you hanging upon it."
The Crocodile brought him to the place. The Monkey leapt off his back, and climbing up the fig-tree, sat upon it.
"O silly Crocodile!" said he; "you thought that there were creatures that kept their hearts in a tree-top! You are a fool, and I have outwitted you! You may keep your fruit to yourself. Your body is great, but you have no sense."
And then to explain this idea he uttered the following stanzas:
Rose-apple, jack-fruit, mangoes too across the water there I see;
Enough of them, I want them not; my fig is good enough for me!
Great is your body, verily, but how much smaller is your wit!
Now go your ways, Sir Crocodile, for I have had the best of it.
The Crocodile, feeling as sad and miserable as if he had lost a thousand pieces of money, went back sorrowing to the place where he lived.